Project Summary/Abstract Senescence and life span modulation are crucial biological processes for all cellular life, controlled through tightly regulated molecular mechanisms. Many of these mechanisms and their modulation are evolutionary conserved, including dietary restriction (DR) and inhibition of the mTOR signaling pathway. While there are likely multiple cellular processes through which such life span modulators act, the full range of molecular phenotypes that cells display as they age under different contexts and genetic backgrounds remains to be characterized. Budding yeast (Saccharomyces cerevisiae) are an excellent model system for this application, as replicative life span (RLS) ? the number of times a mother cell buds before reaching senescence ? is a quantifiable measure of aging that can be collected for yeast on experimental timescales. For my dissertation research, I propose to use state-of-the-art biochemical and proteomic tools to characterize the molecular phenotypes of life span extension in yeast. In SPECIFIC AIM 1, we will construct molecular phenotypes for yeast mutants whose genotypes are associated with extended replicative lifespan. In SPECIFIC AIM 2, we will determine key proteins that induce lifespan extension in yeast upon intervention with modulators. The proposed research revisits previous yeast aging collaborations within my mentoring team, while being innovative in the use of a novel mass spectrometry-based quantitative proteomics that I recently developed. I expect to the resulting molecular phenotypes will replicate known processes such as mitochondrial respiration, reveal novel protein members of established processes, and discover processes not yet associated with yeast longevity.